This invention relates to ultrasonic scanning and detection systems and more particularly to ultrasonic scanning and detection systems capable of providing angular resolution through a full radial arc.
Prior art scanning arrangements have included systems as shown in U.S. Pat. Nos. 4,185,501 and 4,466,286. In contrast unique features of the present apparatus and system include a single transducer apparatus and detection system instead of an array of transducers, in which a full radial arc can be inspected in a single path.
Inside corners on metallic and non-metallic structural members frequently require inspection for delamination and cracks. The cross section of an inside corner is usually a circular arc of known radius. A complete examination of such areas requires the use of ultrasonic inspection. This inspection is difficult because the second beam must:
(a) physically scan across the radius to provide thorough coverage; PA1 (b) remain perpendicular to the parts surface at all times to provide a known internal beam and a front surface echo for gaining setting and time reference; and PA1 (c) be reliably coupled into the part.
Prior attempts have included the utilization of an ultrasonic shoe with a number of transducers oriented at different angles into the radius which systems however have not provided sufficient angular resolution nor provided a moving beam for display generation. In addition, in such systems portions of the radial arc remain uninspected because the transducer case and the part surface coincide at extreme angles. Use of a single transducer scanned by hand along the radial arc as done in the prior art does not provide reproducible data, and does not allow display generation, and does not inspect the extremes of the arc. Also, use of a single transducer mounted in a fixture and scanned along the radial arc does not inspect the extremes of the arc. Use of various through transmission methods provides no information on depth or angular position on the arc.
Use of methods which require that test parts be immersed in a tank of water to provide ultrasonic coupling is impractical. An oil covered, water filled boot mounted on the active face of the transducer provides unreliable coupling on rough surfaces.
It is accordingly an object of the present invention to provide a system and apparatus for pulse echo inspection of laminated parts through a full radial arc.
It is yet another object of the present invention to provide a system which includes motorized reflector control for producing an intensity modulated image in a television type video display. It is still another object of the present invention to provide a variable angle transducer positioner for radius inspection of graphite/epoxy blade stiffened structures to inspect a ninety degree window through a radius and delta areas. It is yet another object of the present invention to provide a variable angle transducer positioner utilizing a 2.25 (MHz) transducer coupled with two reflectors that project sound into a radius from its center point which ultrasonic transducer positioner enables variable angle ultrasonic inspection using the pulse-echo method with water as the couplet.
It is still another object of the present invention to provide a ultrasonic signal processing system for controlling mirror rotation in a variable angle transducer positioner apparatus thereby providing an interrogating sound beam which returns ultrasonic echoes in the presence of delaminations in a laminated part being inspected, the ultrasonic signal processing system further providing echo signal processing input signals to a video display device.
Further objects and advantages of the present invention will become apparent from the following detailed description hereinafter with reference to the accompanying drawings.